shoes/shoes4 — pull request #569 by djsmentya (2014-01-09 08:09:17+00:00)
Title: stop animate the same way as on shoes3

now it should be the same behavior in shoes3 and shoes4
```ruby
Shoes.app do
@animation = animate(20) {para "test"}
button 'abort' do
@animation.stop
@animation = nil
@animation = animate(20) {para "test2"}
end
end
```